Condiment or prepared mustards (i.e., mustard pastes) generally fall into the classes of mild and pungent mustards.
Mild mustards, such as typical yellow mustards, are usually formulated with yellow, often called white, mustard seed (i.e., Sinapis alba a.k.a. Brassica hirta) and have no appreciable pungency. Although very fresh yellow mustard may exhibit some degree of pungency due to the presence of para-hydroxy benzyl isothiocyanate, it is a short-lived, transient effect. Yellow mustards are widely recognized and desired for their mild, non-pungent flavor. Typically, yellow mustards are prepared by mixing the ingredients which include water, vinegar, yellow mustard seed, salt, spices, and tumeric and then fully grinding these ingredients. In this process, the entire yellow mustard seed remains in the resulting mustard paste.
Pungent mustards utilize brown mustard seeds generically which are known to include: brown (i.e., Brassica juncea), oriental (i.e., yellow-coated Brassica juncea), and black (i.e., Brassica nigra) mustard seeds. Such mustards are known and valued for their nose-clearing, volatile "hotness" or pungency. Such mustards contain various levels of the volatile oil of mustard known as allyl isothiocyanate.
In some countries, such as France, dijon mustards cannot contain yellow mustard seed. However, in other countries, yellow mustard seed may be used in conjunction with brown mustard seed in dijon mustards to ameliorate the high pungency produced by the brown seed. It has also been attempted to utilize only yellow mustard seed in preparing a dijon mustard. Such products, however, tend to be of, at best, mediocre quality because the mustard is mild and has little if any dijon flavor character.
Dijon mustard is typically prepared by coarsely grinding mustard seed with water, vinegar, salt, and spices. Following such coarse grinding, the mustard seed bran is separated from the mustard paste by screening to produce a fine textured, pungent mustard with a distinctive dijon flavor. In country-type dijon mustards, the bran is not removed but remains in the mustard to impart a pleasant chunky, coarse appearance and country flavor.